The present invention relates to a ventilator structure of the type that is normally disposed in the foundation of a dwelling or other building structure. Particularly, the present invention relates to a ventilator having an adjustable installation device to adapt the size of the ventilator to improperly sized installation openings.
An automatic ventilator, such as shown in U.S. Pat. No. 4,210,279, which is hereby incorporated herein by reference, has one or more shutters received in a passageway and connected by some means to a thermally responsive spring, such as a bimetallic spring, whereby the shutters automatically open and close, depending upon the ambient temperature. A device for securing the ventilator into an opening is disclosed in U.S. Pat. No. 4,493,456, which is hereby incorporated herein by reference, and employs a threaded set screw and a non-rotational element. To facilitate installation of such ventilators, it is desirable to be able to provide some means of varying the installation dimensions of the ventilator. One such device employing a compression spring is disclosed in U.S. Pat. No. 4,587,892. However, this device provides a rotational axis through screw 35 and spring 36. The ventilator is likely to move about this axis upon impingement of air currents on the ventilator. The range of rotation depends upon how much space develops between the exterior wall surface and the rear surface of flange 16. This kind of movement can cause annoying noises when the flange suddenly contacts the front surface of the wall as air currents impinge upon the ventilator in a manner that causes the ventilator to rotate about the axis formed through screw 35 and spring 36. Moreover, the '892 device is not controllably adjustable, i.e., the adjustment device is not subject to the control of the person installing the ventilator into the opening.